Check engine light on, no coolant reading on display. on 2008 Chevrolet Cobalt

Wife was driving car when check engine light came on. She checked display, all working except no coolant reading was displayed. Where should we start?

1 answer
Check the coolant level. If its low, top if off with proper GM coolant.
If the coolant level is correct (radiator and overflow bottle), have a reputable shop check and diagnose the cooling system for possible sensor problems.